An Optogenetic Method to Study Signal Transduction in Intestinal Stem Cell Homeostasis

J Mol Biol. 2020 May 1;432(10):3159-3176. doi: 10.1016/j.jmb.2020.03.019. Epub 2020 Mar 20.

Abstract

Homeostasis in adult organs involves replacement of cells from a stem cell pool maintained in specialized niches regulated by extracellular signals. This cell-to-cell communication employs signal transduction pathways allowing cells to respond with a variety of behaviors. To study these cellular behaviors, signaling must be perturbed within tissues in precise patterns, a technique recently made possible by the development of optogenetic tools. We developed tools to study signal transduction in vivo in an adult fly midgut stem cell model where signaling was regulated by the application of light. Activation was achieved by clustering of membrane receptors EGFR and Toll, while inactivation was achieved by clustering the downstream activators ERK/Rolled and NFκB/Dorsal in the cytoplasm, preventing nuclear translocation and transcriptional activation. We show that both pathways contribute to stem and transit amplifying cell numbers and affect the lifespan of adult flies. We further present new approaches to overcome overexpression phenotypes and novel methods for the integration of optogenetics into the already-established genetic toolkit of Drosophila.

Keywords: Drosophila; EGFR; Toll; optogenetics; stem cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Communication
  • Cell Proliferation
  • Cells, Cultured
  • Drosophila Proteins / metabolism
  • Drosophila melanogaster / growth & development*
  • Drosophila melanogaster / metabolism
  • Gene Expression Regulation
  • Gene Regulatory Networks*
  • Homeostasis
  • Intestinal Mucosa / cytology*
  • Intestinal Mucosa / metabolism
  • Light
  • Longevity
  • Optogenetics / methods*
  • Signal Transduction
  • Stem Cells / cytology
  • Stem Cells / metabolism

Substances

  • Drosophila Proteins